The knowledge needed to operate systems, both simple and complex, is often expressed in recorded procedures. Procedures describe the processes by which a device or system is operated, and are directed to achieving a task or goal relevant to the system. The information recorded in a procedure is generally derived from system experts and experience acquired as a system is operated over time. Complex systems, such as space vehicles, refineries, etc., may employ thousands of recorded procedures to ensure proper operation of the many facets of the system.
Procedures are conventionally recorded in natural language (i.e., natural human language, such as English) using word processing or text editing tools, and the recorded procedures are displayed via a static medium, such as paper. Alternatively, procedures may be electronically recorded, and presented on an electronic display for manual execution. Electronically recorded procedures are easily modified and, in cases where a large number of procedures are required, can be stored and accessed more conveniently than procedures recorded and/or presented on paper.